http://nativeamericans.mrdonn.org/stories/bluerock.html
I use Michael's web side and write that.

There are four monsters in the villege. A chrid challenge them. they all have four arrow to shut each other.If the boy win. They can eat the monsters' food. Before the challenge day the boy gets the blue rock.He think it's god's gift .Finally the boy beat the monsters ,so the people think is all be come the blue rock.

I thunk this story is want tell us why blue rock is a luck for Apache. It's just a coincidence. Just because the boy beat the monstera ,and he bringing the blue rock.It's rewally cool and inpossible.